| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.5 194/238] mmc: sdhci: further fix for DMA unmapping in sdhci_post_req() | Date | Sun, 10 Apr 2016 11:36:11 -0700 |
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4.5-stable review patch. If anyone has any objections, please let me know.
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From: Russell King <rmk+kernel@arm.linux.org.uk>
commit 771a3dc225815b7cc691c1ce703a3af8488e48df upstream.
sdhci_post_req() exists to unmap a previously mapped but already finished request, while the next request is in progress. However, the state of the SDHCI_REQ_USE_DMA flag depends on the last submitted request.
This means we can end up clearing the flag due to a quirk, which then means that sdhci_post_req() fails to unmap the DMA buffer, potentially leading to data corruption.
We can safely ignore the SDHCI_REQ_USE_DMA here, as testing data->host_cookie is entirely sufficient.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> [ Re-based to apply as a separate fix ] Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/mmc/host/sdhci.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
--- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2115,14 +2115,13 @@ static void sdhci_post_req(struct mmc_ho struct sdhci_host *host = mmc_priv(mmc); struct mmc_data *data = mrq->data; - if (host->flags & SDHCI_REQ_USE_DMA) { - if (data->host_cookie == COOKIE_GIVEN || - data->host_cookie == COOKIE_MAPPED) - dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, - data->flags & MMC_DATA_WRITE ? - DMA_TO_DEVICE : DMA_FROM_DEVICE); - data->host_cookie = COOKIE_UNMAPPED; - } + if (data->host_cookie == COOKIE_GIVEN || + data->host_cookie == COOKIE_MAPPED) + dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, + data->flags & MMC_DATA_WRITE ? + DMA_TO_DEVICE : DMA_FROM_DEVICE); + + data->host_cookie = COOKIE_UNMAPPED; } static int sdhci_pre_dma_transfer(struct sdhci_host *host,
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